01Science

Weather is Tuesday, climate is the average of thousands of Tuesdays

Weather is the specific report: rain, 14 degrees, wind from the west. Climate is the statistics of weather over a long stretch, commonly averaged over 30 years, including how often extremes show up. That is why one brutal cold snap tells you nothing about long term warming, and why forecasters lose accuracy after roughly a week while still saying useful things about the 2050s.

Most arguments about a hot week or a freak blizzard are really confusion between a single day and an average.

02Ideas

The economics Nobel is not Nobel's; a central bank created it in 1968

Alfred Nobel's will funded five prizes: physics, chemistry, physiology or medicine, literature, and peace. Economics is not among them. Sweden's central bank, the Sveriges Riksbank, endowed a separate award in economic sciences in memory of Nobel in 1968, first given the following year. It is announced alongside the others and handed out at the same Stockholm ceremony, which is why almost everyone calls it a Nobel. Some of Nobel's descendants have objected to that.

Lets you answer both versions of the question: five original prizes, six awards announced each year.

03Tech

A touchscreen finds your finger because your body drains charge from a grid

Under the glass sit two layers of a transparent conductor, laid as fine strips crossing each other like graph paper. Each crossing holds a tiny electrical charge. Your finger is mostly salty water, which conducts, so bringing it close pulls some of that charge away and the chip notices which crossings dropped. No pressure is involved, which is why glass is no obstacle and a feather-light tap works. It also explains why a wool glove or a fingernail does nothing, and why water spilled on the screen produces ghost taps.

Explains every touchscreen frustration you have had, from gloves in winter to a phone going haywire in the rain.

04World

About 8 billion people are alive, and roughly three in four live in Asia or Africa

China and India each hold around 1.4 billion, so either one alone is close to a sixth of everyone alive. The United States, at about 340 million, is a bit over 4 percent. All of Europe together is under 10 percent. Most people picture humanity as far more Western than it is, which quietly distorts guesses about market sizes, emissions, and how a typical person actually lives.

Almost every claim about "people" is really a claim about a slice, and this tells you how big the slice is.

05Money

Accrual accounting books a sale when you deliver it, not when you get paid

Say you finish a job in December and the client pays in March. Under accrual accounting, the revenue belongs to December, because that is when you did the work, and the costs of doing it get recorded in December too. Cash accounting, which is how most people think about their own money, would put the whole thing in March. Public companies use accrual. That is exactly why reported profit can exist while the bank account sits empty.

It explains why the profit figure and the money in the account describe two different moments in time.

06World

The Nile or the Amazon is longest, depending on where you say a river begins

Reference books usually give the Nile about 6,650 km and the Amazon about 6,400 km, and that is the answer most quizzes want. The gap is small enough that definitions decide it. The Amazon has several candidate source streams high in the Peruvian Andes, and its mouth spreads into a huge estuary with no obvious cut-off point. Pick the far source and a distant mouth and the Amazon wins. Geographers genuinely disagree.

Shows that the biggest facts in geography often rest on a measuring convention rather than a measurement.

07Money

Every transaction is written down twice, which is how mistakes get caught

Buy a van for 20,000 in cash and two things happen at once: a van appears among what you own, and cash drops by 20,000. Double entry bookkeeping means recording both halves of every event, so the two columns must agree at the end. If they don't, something was mistyped or missed. It won't catch a wrong number entered correctly in both places, or a deliberate lie.

It explains why accounts are built as paired columns rather than a single running list of payments.

08World

Napoleon was average height; the myth comes from a different inch

At his death he was recorded as 5 feet 2 inches, measured in French units, and the French inch of the time was longer than the English one. Convert properly and he lands near 5 foot 6, unremarkable for a Frenchman of his era. Two things fed the legend. British cartoonists drew him as a tiny raging man, and his personal guard were chosen partly for size, so he looked small standing among them.

A famous fact about a famous man turns out to be a unit conversion error repeated for two centuries.

09Ideas

The First Amendment restrains the government, not your boss

The text opens with "Congress shall make no law," and through the Fourteenth Amendment it now binds state and local government too: police, city councils, public schools, public universities, the DMV. A private employer who fires you over a post, a social platform that deletes it, a private college that disciplines you, none of them are the government, so no free speech claim arises. Other law, like a labor contract or a state statute, might still protect you.

It settles the most common argument people have about censorship, before it starts.

10World

The Great Wall is not visible from space with the naked eye

The wall is only a few metres wide in most places, built from local stone and earth, so it blends into the ground around it. From orbit you are looking for a thin line the colour of the hills beside it. Chinese astronaut Yang Liwei reported he could not pick it out. From the Moon, Earth is a small bright marble and no human structure shows at all. The claim was in print before anyone had flown to space.

Recalibrates how small human construction is against the scale of a planet.

11Money

A balance sheet balances because everything a company owns was paid for by someone

Two claims exist on every asset. Lenders and suppliers have first claim, which is liabilities. Whatever is left over belongs to the owners, which is equity. So assets always equal liabilities plus equity, by construction rather than by luck. A bakery with 500,000 of ovens and stock, and a 400,000 loan, has 100,000 of equity. If the ovens lose value, equity absorbs the hit.

Once you see assets as claims, you can tell instantly how much of a business the owners really hold.

12Tech

Wifi is radio, and the faster 5 GHz band is the one walls stop

Your router is a radio transmitter running on a fraction of a watt, with your data encoded as rapid changes in the wave. On the 2.4 gigahertz band the waves are roughly 12 centimetres long and get through brick reasonably well. At 5 gigahertz they are around 6 centimetres, carry more data per second, and are absorbed or bounced away sooner. Water absorbs both, which is one reason a room full of people weakens the signal.

Tells you which band to join at the far end of the house, and why moving one room closer fixes so much.